---
cve: "CVE-2026-77776"
severity: "CRITICAL"
cvss: 9.3
epss: "0.3%"
vendor: "Headroom Labs"
kev: false
exploited: false
published: "2026-08-21 12:16:36"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-25T00:01:08+02:00"
---

# CVE-2026-77776

> 9.3 CRITICAL · 🧪 PoC

## Beschreibung

Headroom's LLM proxy derives the memory owner from the x-headroom-user-id request header. The header is read directly at several points in headroom/proxy/handlers/openai.py, including the chat completion and websocket paths, and nothing binds the value to the caller. A client can therefore name another user's identifier and read or write that user's stored LLM memory. The fix introduces a single resolve_memory_identity seam in headroom/proxy/identity.py that honors the header only for loopback or allowlisted callers and otherwise binds the identity to the proxy-token fingerprint or the operating system user. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOM_PROXY_TOKEN, which the server itself warns about at startup, so a deployment following the shipped compose exposes the affected data-plane routes to the network without authentication.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 37faf2f24724370483b1819b0921c899791bedc7 (Commit)

## Referenzen

- <https://github.com/headroomlabs-ai/headroom/pull/2207>
- <https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py>
- <https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/identity.py>
- <https://github.com/headroomlabs-ai/headroom>
- <https://www.vulncheck.com/advisories/headroom-proxy-treats-the-client-supplied-x-headroom-user-id-header-as-an-authenticated-identity>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-77776) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_